Urban gardens: Lead exposure, recontamination mechanisms, and implications for remediation design
Urban gardens: Lead exposure, recontamination mechanisms, and implications for remediation design
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DOI：
10.1016/j.envres.2008.03.003
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发表时间：
2008-07-01
影响因子：
8.3
通讯作者：
Brabander, Daniel J.
中科院分区：
文献类型：
--
作者：
Clark, Heather F.;Hausladen, Debra M.;Brabander, Daniel J.
环境铅污染在城市地区普遍存在，土壤是一个重要的汇和接触途径。这项研究的特点是铅的形态，是有关当地的再污染和人类接触的后院花园的罗克斯伯里和多切斯特，MA，美国。141个后院花园进行了X射线荧光测试，81%的花园铅含量超过美国环保局行动限制400微克/克。高架园艺床是社区推广城市园艺的原位减少暴露方法。对高架床进行了铅含量测试，结果表明，铅浓度在4年内从最初的150 +/- 40微克/克增加到平均336微克/克。细颗粒土壤（< 100 μ m）中铅的百分比分布和隆起床的痕量金属特征支持再污染机制是风输送颗粒的结论。扫描电子显微镜和连续提取被用来表征铅的形态，和微量金属签名的细粒土壤在花园和提出园艺床是铅基涂料的特点。这项研究表明，提高床是一种有限的减少暴露的方法，需要维护，以实现减少暴露的目标。基于一套参数开发了一个暴露模型，该参数将文献中的联合收割机相关值与特定地点的暴露途径量化相结合。该模型表明，食用自产农产品仅占儿童每日铅暴露量的3%，而摄入细粒土壤（< 100 μ m）占每日铅暴露量的82%。这项研究表明，在一个院子里的院子规模的城市铅修复需要不断的维护，修复可能需要发生在一个街区范围内的规模。(C)2008年爱思唯尔公司All rights reserved.
Environmental lead contamination is prevalent in urban areas where soil represents a significant sink and pathway of exposure. This study characterizes the speciation of lead that is relevant to local recontamination and to human exposure in the backyard gardens of Roxbury and Dorchester, MA, USA. One hundred forty-one backyard gardens were tested by X-ray fluorescence, and 81% of gardens have lead levels above the US EPA action limit of 400 mu g/g. Raised gardening beds are the in situ exposure reduction method used in the communities to promote urban gardening. Raised beds were tested for lead and the results showed that the lead concentration increased from an initial range of 150 +/- 40 mu g/g to an average of 336 mu g/g over 4 years. The percent distribution of lead in the fine grain soil (< 100 mu m) and the trace metal signature of the raised beds support the conclusion that the mechanism of recontamination is wind-transported particles. Scanning electron microscopy and sequential extraction were used to characterize the speciation of lead, and the trace metal signature of the fine grain soil in both gardens and raised gardening beds is characteristic of lead-based paint. This study demonstrates that raised beds are a limited exposure reduction method and require maintenance to achieve exposure reduction goals. An exposure model was developed based on a suite of parameters that combine relevant values from the literature with site-specific quantification of exposure pathways. This model suggests that consumption of homegrown produce accounts for only 3% of children's daily exposure of lead while ingestion of fine grained soil (< 100 mu m) accounts for 82% of the daily exposure. This study indicates that urban lead remediation on a yard-by-yard scale requires constant maintenance and that remediation may need to occur on a neighborhood-wide scale. (C) 2008 Elsevier Inc. All rights reserved.